Workers will recognize that various techniques are known for confronting magnetic recording media with a magnetic recording transducer face. For instance, according to one technique, the transducer face is brought into contact with the passing medium. According to another technique ("non-contact" recording) the transducer face is virtually "flown" above the medium and kept out of contact therewith as a guard against damage to the medium, to the face or both. Generally speaking, workers prefer such "out-of-contact" techniques where feasible. This invention concerns an improvement in "non-contact recording" and an associated novel configuring of the transducer face.
Magnetic memory storage units are a significant item of peripheral equipment in today's computers. In the typical unit data is stored on one or several magnetic disk drives. Such a drive will be recognized as characterized by one or more rotating magnetic recording surfaces on which data may be written, and read back, by a magnetic transducer mounted in a recording head. Such heads are "flown" in close proximity above a recording surface. Great care is taken that this flying head never "crashes" against the disk since catastrophic damage to both can result. Yet, to maximize recording density and optimize signal/noise, workers know that the "head spacing" (spacing between the head-face, and core there, and the surface of the moving disk) must be kept as small as possible and be held within very tight tolerances.
It is common to establish "head spacing" for a "flying head" by configuring the head-face in the fashion of an "air bearing" while establishing the proper fluid dynamics. The magnetic head surface is, today, mounted on a resilient suspension and urged toward the surface of the moving disk by a head actuation means, but is prevented from actual disk contact by an intervening cushion of air--called a "Bournoulli film" and established as the air bearing. Once this Bournoulli film is developed, it presents a rather substantial hydrodynamic resistance to reduction of "head-spacing" and significant force must be exerted to push the head closer to the disk. But certain abnormal conditions can disturb this "Bournoulli film" and suddenly remove it as a protective cushion, sending the head crashing into the disk. Thus, workers in the art are very meticulous in developing the proper (aerodynamic) head-face configuration and in positioning the head so as to properly orient it (e.g., re pitch and roll angles) relative to the passing disk such close tolerances that a change of a minute of arc or so can be critical!
Worker know that it is critically important to maintain a predictable constant "head spacing" over a wide range of operating parameters if magnetic recording is to be successful. Head spacing is particularly critical with high density recording--e.g., it can vary the "fringing flux" pattern and affect read/write resolution.
The foregoing relates, mainly, to rigid media technology and--as workers are beginning to realize--is not necessarily applicable to flexible disks. This invention is particularly concerned with improved transducer configurations especially adapted for "near-approach" to floppy disk media during read/write sequences.
Workers also know that there are many factors affecting head spacing; such factors as the speed, configuration "penetration" and radial-position of a head [understand: "head speed" as the relative velocity between medium and transducer and "head penetration" as the penetration of the transducer stabilizer combination into the plane of the passing record medium, causing the latter to "dimple"]. Other affecting factors are disk characteristics (e.g., flexibility, thickness, etc.) and ambient conditions such as temperature and humidity.